Longer Exposure Times Research Articles

Curcumin-Loaded Lipid Nanoparticles: A Promising Antimicrobial Strategy Against Enterococcus faecalis in Endodontic Infections

Background/Objectives: This study aims to evaluate the efficacy of curcumin (CUR), a natural polyphenol with potent antimicrobial and anti-inflammatory properties, when formulated as solid lipid nanoparticles (CUR-loaded SLN) against Enterococcus faecalis. Methods: Solid lipid nanoparticles (SLNs) were prepared as a carrier for CUR, which significantly improved its solubility. SLNs made with cetyl palmitate and Tween 80 were obtained via the hot ultrasonication method. The physicochemical properties of CUR-loaded SLNs were evaluated, including their size, stability, and release profile. Antimicrobial testing was conducted against both sessile and planktonic E. faecalis populations. Cytotoxicity was assessed on human gingival fibroblasts. Results: The CUR-loaded SLNs exhibited about 200 nm and a −25 mV surface potential, and the encapsulation of CUR did not affect the physicochemical properties of SLNs. CURs were released from SLNs in a controlled and sustained manner over 100 h. The nanoparticles remained stable for at least two months when stored at 4 °C or 25 °C, making them suitable for clinical use. Antioxidant activity was confirmed through DPPH and ABTS assays. Free CUR significantly reduced the planktonic E. faecalis CFU counts by approximately 65% after 24 h of exposure. However, this inhibitory effect diminished with longer exposure times (48 and 72 h). Antimicrobial activity studies of CUR-loaded SLNs showed dose- and time-dependent effects, in the 2.5–10 µg/mL range, against both sessile and planktonic E. faecalis populations, over 24 to 72 h. The CUR-loaded SLNs showed good cytocompatibility with human fibroblasts up to 2.5 μg/mL, suggesting low toxicity. Conclusions: CUR-loaded SLNs demonstrate significant antimicrobial activity against E. faecalis, along with good cytocompatibility, indicating their potential as an effective adjunct therapy in endodontic treatments.

Alkali Pretreatment of Lignocellulose Feedstock Improves Morphological Structure and Biomethane Yield

This study investigates the effects of NaOH pretreatment on the microstructural distribution and biomethane released from Xyris capensis. Xyris capensis was pretreated with NaOH using 1, 2, 3, 4, and 5% w/w concentrations for 60, 45, 30, 20, and 15 min of exposure time, respectively, at a 90 °C autoclave temperature. The impacts of the pretreatment technique on microstructural arrangement, crystallinity, and functional groups were examined with a scanning electron microscope (SEM), X-ray diffraction, and Fourier transform infrared (FTIR), respectively. NaOH-pretreated and untreated feedstocks were digested at the laboratory scale at a mesophilic temperature (37 ± 2 °C) for 35 days for their biomethane potential. It was discovered from the SEM analysis that NaOH pretreatment affects the microstructural arrangement of Xyris capensis, and the sample with the longer exposure time is the most affected. The results of XRD and FTIR also indicated that NaOH pretreatment lowered the crystallinity of the feedstock and significantly influenced the functional groups at varying degrees. Biomethane yield was recorded to be 258.68, 287.80, 304.02, 328.20, 310.20, and 135.06 mL CH4/gVSadded, representing 91.53, 113.09, 125.10, 143.00, and 129.68% more increases than the untreated feedstock. It was discovered that the optimum biomethane generation was achieved when 4% w/w of NaOH concentration was utilized for 20 min. This study shows that a higher NaOH concentration with a shorter retention time is more suitable for Xyris capensis. This pretreatment method can improve the biomethane yield of Xyris capensis and can be investigated for industrial applications and its use on other lignocellulose feedstocks, especially energy grasses.

Evaluation of the frequency and risk of corona virus in different occupations of a teaching hospital in Yazd City

Introduction: Healthcare professionals are the frontline soldiers against Corona. Materials and Methods: This cross-sectional study was conducted on all personnel at a teaching hospital located in Yazd City. Each participant completed a questionnaire that included demographic information as well as their history regarding the frequency and length of daily contact with a patient infected with COVID-19. It also covered the duration of personal protective equipment (PPE) usage and alcohol-based hand rub application during direct exposure (with 1 meter) and throughout aerosolizing procedures performed on the patient. Incidence rate, Frequency rate, probability, severity rate, and risk of corona infection were evaluated among various occupational groups within the hospital. Results: 40.66% of the staff employed in the hospital were infected with corona virus. The highest frequency of corona infection was observed among nurses (51.60%). Over 90% of healthcare personnel who did not utilize PPE for 95% of their work time faced a high-risk level for the coronavirus. Physicians reported the highest number of daily exposures (averaging 27.94 exposures) and the longest exposure time (averaging 243.89 minutes). The highest risk of infection among doctors (60.93) and nurses (39.49) was observed. The nurses exhibited the highest incidence rate (51.22) and frequency rate (26.27). Conclusion: Due to a significant percentage of hospital staff with coronavirus, and with the highest infection rates occurring among nurses, adequate training for the use of PPE is necessary.

Effects of Ultraviolet-C (UV-C) radiation on germination, seedling growth, and abiotic stress response in waxy corn (<em>Zea mays</em> L.)

Waxy corn (Zea mays L.) is an important crop in the Philippines, but its production has been hampered by various abiotic stresses, including waterlogging and salinity. This study investigates the potential of using UV-C radiation as a strategy to improve the growth performance of waxy corn under these stressful conditions. The study utilized a completely randomized design to evaluate the effects of different durations of 254 nm UV-C radiation (0, 30, 60, 90, & 120 min) on the germination and early seedling growth of waxy corn. Germination parameters and seedling growth under normal, waterlogged, and saline conditions were evaluated. The results showed that moderate UV-C exposure (30–60 minutes) had a beneficial effect on waxy corn seed germination, with significantly higher germination percentages and faster times to reach 50% germination compared to the control. However, longer exposure times (90–120 minutes) had a detrimental impact on germination. For seedling growth, moderate UV-C exposure (30–60 minutes) generally had a stimulatory effect, increasing various growth parameters under normal and waterlogged conditions. Longer exposure times (90–120 minutes) resulted in values closer to or not significantly different from the control. Under saline stress, increasing UV-C exposure time had a generally positive effect on seedling growth, with the optimal duration being around 90 minutes. The findings of this study suggest that the optimal duration of UV-C exposure for enhancing waxy corn germination and seedling growth varies depending on the specific environmental conditions. Moderate UV-C exposure (30–60 minutes) can be beneficial for improving seed germination and early seedling growth under normal and waterlogged conditions, while longer exposure times (> 90 minutes) are more suitable for enhancing growth under saline stress.

Antimicrobial photodynamic inactivation of Pseudomonas aeruginosa persister cells and biofilms.

Pseudomonas aeruginosa is a hard-to-treat human pathogen for which new antimicrobial agents are urgently needed. P. aeruginosa is known for forming biofilms, a complex aggregate of bacteria embedded in a self-generated protective matrix that enhance its resistance to antibiotics and the immune system. Within the biofilm, persister cells, sub-populations of slow-growing or growth-arrested cells, are associated with recalcitrance of infections and antibiotic treatment failure. Here, we investigate the influence of the anionic photosensitiser chlorophyllin (CHL)1 exposed to red light alone and in combination with an activator of the mechanosensitive channels butylparaben (BP) on P. aeruginosa growing cells, persister cells, and biofilms. Antimicrobial susceptibility tests were performed using the broth microdilution checkerboard method. Serine hydroxamate (SHX) was used for the induction of persister cells. Under illumination, a combination of CHL (250 µg/ml) and BP (97.12 µg/ml) reduced the number of growing cells and persister cells by 2.2±0.46 log10 and 1.7±0.15 log10, respectively after 30 min of exposure at 79 J/cm2. A higher concentration of BP (194.23 µg/ml) or longer exposure time (60 min at 158 J/cm2) effectively eliminated approximately ≥99.99 % of growing and persister cells. Visual evidence from confocal and TEM images illustrates the influence of CHL and red light, which intensifies when combined with BP. Nevertheless, the addition of BP did not enhance the efficacy of CHL against biofilms; CHL (500 µg/ml) reduced biofilm viability by 2.6 log10 at 791 J/cm2. No toxicity has been observed in darkness. This study highlights the potential antimicrobial effect of CHL against P. aeruginosa.

Towards Highly Stable Sn2+ Electrolyte for Aqueous Tin Batteries Using Hydroquinone Antioxidant.

Sn redox chemistry in aqueous acidic electrolyte was characterized with high reversibility and kinetics, which is considered as competitive anode material for aqueous batteries. Unfortunately, divalent Sn2+ is unstable in aqueous electrolyte. It was revealed that Sn2+ is easy to be oxidized to tetravalent Sn4+ by dissolved oxygen and then forms precipitate through hydrolysis process, leading to serious performance decay. Here, hydroquinone (HQ) was employed as antioxidant to prevent Sn2+ oxidation. With addition of HQ, Sn2+ electrolyte can maintain transparent and colorless after long-time exposure under air atmosphere, while large amounts of sediment were observed in the electrolyte without HQ. Moreover, HQ can adsorb on electrode surface to regulate Sn deposition and suppress Sn dendrite formation. With the difunctional HQ additive, Sn anode shows a stable cycling performance more than 1500 cycles with a high average coulombic efficiency (CE) of 99.9%. And the organic||Sn cell shows high cycling stability for 10,000 cycles with 71% capacity retention. The hydroquinone antioxidant strategy provides a facile and cost-effective way to develop highly stable Sn2+-based electrolyte.

The effects of acute operational stress and passive heat stress on physiological and subjective stress responses in military personnel.

Military personnel often encounter situations that can trigger acute stress, which may affect operational performance. Therefore, it is important to examine stress responses in controlled environments to obtain more insights in performance-influencing effects of acute stress. This study investigated the impact of passive heat exposure combined with virtual combat scenarios on cardiovascular and psychophysiological parameters in a controlled setting. Sixty-eight healthy servicemembers were randomized into a low-stress or high-stress condition. Both groups engaged in two virtual combat scenarios. The low-stress group, however, underwent testing under thermoneutral conditions (MTemp = 22.4 °C, MRelativeHumidity = 41.4 %) whereas the high-stress group was exposed to passive heat exposure (MTemp = 35.9 °C, MRelativeHumidity = 66.4 %) using a portable environmental facility. While virtual combat scenarios alone led to a decrease in heart rate variability (HRV) without affecting heart rate (HR), the addition of passive heat exposure elicited a more pronounced physiological stress response, characterized by significantly higher HR and lower HRV in the high-stress condition. However, no significant changes were observed in respiratory rate, salivary cortisol, or alpha-amylase levels across the conditions, suggesting that there was no activation of either the hypothalamic-pituitary-adrenal or the sympathetic-adrenal-medullary axis. Furthermore, subjective stress and anxiety scores did not differ between conditions, underscoring the physiological nature of the observed changes. Resultantly, the physiological response was likely a thermal reaction rather than an acute stress response. These findings highlight the importance of incorporating environmental stressors into military training protocols to enhance realism and prepare personnel for operational stressors. However, the mild response observed suggests that higher ambient temperatures and longer exposure times may be necessary to evoke a more robust stress response for effective stress inoculation training.

Mortality and Repellency Effect of Some Essential Oils against Tribolium castaneum (Coleoptera: Tenebrionidae)

The red flour beetle (Tribolium castaneum) is a major pest of stored grains, causing significant economic losses. In recent years, essential oils have gained attention as eco-friendly alternatives to synthetic pesticides. This study evaluated the insecticidal and repellent properties of three essential oils—lavender (Lavandula spica), mogra (Jasminum sambac), and rose (Rosa damascena)—against T. castaneum. Toxicity was assessed using direct contact and fumigation methods, targeting adult T. castaneum, respectively. Repellency was tested on larvae using filter paper assays and bioassays were conducted at varying doses and exposure durations. In direct contact assays, adult mortality increased with higher doses and longer exposure times. Lavender oil showed the highest toxicity (LD50 = 0.366–0.143 µl/cm²), followed by Mogra oil (LD50 = 1.037–0.147 µl/cm² at 3–48 h) and rose oil (LD50 = 0.651–0.188 µl/cm²). In fumigation assays, rose oil was the most effective against the target insect (LD50 = 4.031–2.252 µl/cm² at 24–48 h), followed by lavender oil (LD50 = 4.980–3.180 µl/cm²) and mogra oil (LD50 = 7.339–5.463 µl/cm²). Overall, the direct contact method was more effective than fumigation. Repellency assays showed mogra oil exhibiting significant effects (F = 25.25, P < 0.001) and achieving 100% repellency at 0.0785 µl/cm² within 3–4 hours, whereas lavender and rose oils showed lower and statistically insignificant effects. This study highlights the potential of essential oils as biopesticides for managing T. castaneum. Mogra oil demonstrated superior efficacy in direct contact assays, while rose oil excelled in fumigation tests. These findings support the use of essential oils as eco-friendly alternatives for pest management in stored grains.

Enhancement of antioxidative potential of mung bean by oxygen plasma irradiation of seeds

The present study aimed to assess the effect of oxygen plasma treatment on the germination rate, growth, and antioxidative activity of mung beans at different pressures and irradiation exposure times. Oxygen plasma was capable of shortening the germination time as well as improving the germination rate at each gas pressure and exposure time compared to control. The germination rate of plasma-treated seeds exceeded 90% within 18 h of seeding compared to 30 h for the control (without plasma treatment). Stem length increased by 25.42 to 52.88% depending on the pressure and exposure time compared to control. Vitamin C content in the stem and root increased from 1.49 to 1.97 and 1.27 to 2.04-fold higher, respectively, depending on the pressure and exposure time compared to control; while in the case of thiol content, it was 1.16 to 2.76 and 1.09 to 2.49-fold higher in the stem and root, respectively. Plasma treatment increased antioxidant potency compared to control. Maximum antioxidant potency was found at 30-min exposure time, although the alterations in pressure did not elicit prominent changes. Plant growth, vitamin C and thiol contents, and antioxidant potency were increased with increasing pressure up to 60 Pa, which then declined with higher pressure. On the other hand, these parameters decreased with a longer exposure time, except for the antioxidants. Thiol and vitamin C contents were associated with plant growth.

The Effect of Terpinen-4-ol on Human Corneal Epithelium.

To investigate the toxicity of terpinen-4-ol (T4O) on primary cultured human corneal epithelial cells (HCECs). HCECs were exposed to various concentrations (0%-0.1%) of T4O for 15minutes to 72hours. Cell viability was assessed using the CCK8 kit and cell counting. Intracellular reactive oxygen species (ROS) were measured after 15 to 60minutes of T4O exposure. Changes in cell morphology and cytoplasmic actin filaments were observed using phase contrast microscopy and immunocytochemistry. The expression levels of proteins involved in cell survival pathways (mTOR, Akt, Bcl-xL, and BAX) were evaluated by Western blot analysis. T4O induced dose-dependent toxicity in HCECs. Exposure to 0.05% T4O for 15minutes significantly decreased cell viability. Lower concentrations (0.025% and 0.0125%) also caused significant toxicity with longer exposure times. Prolonged exposure enhanced cytotoxicity, with 0.05% T4O reducing viability by half after 24hours and 0.1% T4O causing complete cell death. Increased intracellular ROS and decreased levels of phosphorylated mTOR, phosphorylated Akt, and Bcl-xL, along with increased BAX expression, accompanied this toxicity. F-actin staining revealed significant changes in cell adhesion. Our study demonstrates that T4O exposure causes significant toxicity in HCECs, depending on concentration and incubation time. This toxic response is associated with increased ROS and decreased cell survival pathway activity. The corneal epithelial toxicity data of T4O revealed in this study may be useful in the future use of tea tree oil or the development of tee tree oil-containing eyelid scrub products for treating eyelid demodex infestation.

Bacterial air contamination and the protective effect of coverage for sterile surgical goods: A randomized controlled trial.

There is limited knowledge regarding how long prepared sterile goods can wait before becoming contaminated. We investigated whether surgical goods could be prepared the day before surgery and kept sterile overnight in the operating room, if protected by sterile covers. Sterile surgical goods for open-heart surgeries (n=70) were randomized to preparation on the morning of the operation or on the previous evening. Exposure time was the total time between preparation and use. Primary outcome was bacterial growth reported as colony forming units (cfu), isolated on 840 agar plates. The protocol was registered with ClinicalTrials.gov (NCT05597072). When the agar plates were protected with sterile covers, exposure time had no impact (intervention group: 7 cfu, control group: 17 cfu). Without protection, longer exposure time was associated with more cfu (p=0.016). A total of 499 cfu were isolated, displaying 59 different types of bacteria including 13 resistant Staphylococcus epidermidis, 6 (46%) of which were multidrug resistant. Sterile goods could wait in the operating room for at least 15 hours before use without increased risk of bacterial air contamination, if protected with sterile covers. However, if the goods were not covered, bacterial air contamination occurred over time.

Surface modification of 3D-printed polycaprolactone- human decellularized bone matrix composite scaffold by plasma for bone tissue engineering

BackgroundBone tissue engineering is a revolutionary field focused on creating viable bone substitutes using advanced materials and techniques. Utilizing 3D printing, precise and customizable bone scaffolds can be produced. A notable composite material in this domain is a composite of polycaprolactone (PCL) and human decellularized bone matrix (hDBM), which combines synthetic and natural elements for enhanced functionality. To further improve cell attachment and growth, cold plasma surface modification is employed, optimizing scaffold surfaces. These innovations collectively hold great potential for improving bone repair and regeneration outcomes. MethodsScaffold architecture was designed through CAD software, and the composite of PCL and hDBM was printed using FDM technology. Surface modification was achieved by exposing the scaffolds to Argon-Oxygen (Ar-O₂) plasma radiation for 1 and 3 minutes. Both treated and untreated scaffolds were characterized, including measurements of surface roughness, hydrophilicity, and cellular activity. ResultsAlmost all groups showed non-toxic effect on cellular behavior during cell culture. Plasma-treated scaffolds showed a significant increase in surface roughness, with roughness values (Ra) increasing from 10.45 nm (untreated) to 62.75 nm after 3 minutes of plasma exposure. Contact angle measurements decreased from approximately 66.5° in untreated scaffolds to 31.4° in those treated for 3 minutes, indicating enhanced hydrophilicity. Plasma-treated scaffolds demonstrated excellent cytocompatibility, significantly enhancing cell proliferation, osteogenic differentiation, and mineralization compared to untreated scaffolds. After 7 days, scaffolds treated for 1 and 3 minutes showed 35% and 60% increases in cell proliferation, respectively, highlighting the role of plasma treatment in creating a bioactive surface conducive to cell adhesion, growth, and improved osteogenic properties, with longer exposure times further amplifying these effects. ConclusionsThe current study demonstrates the efficacy of Ar+O₂ plasma treatment in enhancing the surface properties of PCL-hDBM scaffolds, making them more conducive to osteogenesis. This study suggests that plasma-treated PCL-hDBM scaffolds are a promising option for bone tissue engineering applications.

Toxicological Effects of Sewage Sludge on Biochemical Biomarkers of Earthworms (Eisenia andrei)

ABSTRACTSewage sludge, or biosolids, produced in wastewater treatment plants (WWTP) can be used as an alternative to organic fertilizer in the agricultural field. However, it holds a large amount of anthropogenic chemicals, such as drugs and metals. The aim of the present study is to evaluate biochemical biomarker responses in earthworms (Eisenia andrei) exposed to soil presenting different sludge concentrations deriving from the largest WWTP in Southern Brazil. Treatments comprised 3%, 6%, 12%, 24%, 50%, and 75% of sludge incorporated to native forest soil, 100% of sludge and the control group (0%). Concentrations of different drugs, mainly of antibiotics, as well as high sulfur, magnesium, potassium, zinc, and phosphorus were identified in analyzed sewage sludge. Exposed earthworms were collected on the 7th, 14th, and 28th day of the experiment and subjected to analysis of lipid peroxidation levels (TBARS), acetylcholinesterase (AChE), catalase (CAT), and glutathione S‐transferase (GST) activity. Treatments with 50%, 75%, and 100% of sludge were lethal to earthworms after 7 days. Based on biochemical tests performed in treatments with 3%, 6%, 12%, and 24% of sludge, the highest sludge concentrations (12% and 24%) and the longest exposure time (28 days) led to significant changes in biomarkers. Therefore, sewage sludge must be incorporated into the soil at concentrations lower than 3%, mainly due to changes in CAT, AChE, GST, and the resulting lipid damage observed at concentrations of 6%, 12%, and 24%.

A mineralogical and geological study for tungsten extraction from alkaline granite in Abu Kharif area, North Egyptian Nubian Shield

ABSTRACT Wolframite-quartz vein-type represents a significant global tungsten resource essential to tungsten production. In the northern Arabian-Nubian Shield (Egypt), such mineralisation is associated with the Abu Kharif alkaline granite (614.6 ± 3.6 Ma). Mineralised quartz veins, containing mixed wolframite ore (603.7 ± 7.4 Ma), occur along the contact between these granites and metavolcanic rocks, accompanied by extensive alkali alteration. Wolframite is the foremost valuable mineral in this ore, along with scheelite and hübnerite. Despite extensive research on Abu Kharif alkaline granites and associated ore, tungsten extraction from the mineralised quartz remains understudied. This study presents an efficient method for tungsten extraction involving two stages: physical beneficiation and chemical processing techniques. An optimal tungsten recovery was achieved using a Na2CO3 fusion leaching technique, yielding a high tungsten trioxide concentration in the tungsten concentrate after chemical scrutiny. Key variables, including temperature, time, and concentrate-to-Na2CO3 ratio, were analysed for their impact on leaching efficiency. Experimental results indicate that the fusion leaching method achieves optimal efficiency with a concentrate-to-Na2CO3 ratio of 1/2.5, a fusion time of 3 h, and a fusion temperature of 600 °C. The fusion leaching tests showed that more reagents, higher temperatures, and longer exposure time did not significantly improve the leaching process.

Influence of neodymium-doped yttrium aluminum garnet laser exposure time on cytokine secretion in lipopolysaccharide-challenged rat peripheral blood mononuclear cells

Multiple investigators have suggested that infrared laser energy facilitates hard and soft tissue wound healing through various mechanisms, including the suppression of inflammation. This study investigated the influence of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser exposure time on pro-inflammatory cytokine/chemokine concentrations in lipopolysaccharide (LPS)-stimulated rat peripheral blood mononuclear cells (PBMCs). Cultured rat PBMCs were stimulated with various LPS concentrations (0, 10, 100, or 1000 ng/mL) and treated with Nd:YAG laser irradiation for 0 (control), 30, 45, or 60 s. For these experiments, the average power, pulse duration, and repetition rate remained constant at 5 W, 100 μs, and 20 Hz, respectively. Luminex magnetic microsphere immunoassays were used to compare the secretion of 27 inflammatory mediators from LPS-stimulated PBMCs in laser-irradiated versus control groups. Two-way analysis of variance was used to compare the main effects of laser exposure time and LPS concentration on cytokine/chemokine concentrations and evaluate the potential interaction between these factors. Four pro-inflammatory cytokines – tumor necrosis factor-α, macrophage inflammatory protein (MIP)-1α, MIP-2, and interferon gamma-induced protein-10 – exhibited a trend of reduced secretion in laser-irradiated cultures. The effect appeared more pronounced at longer exposure times (45 and 60 s). However, none of the 27 inflammatory mediators exhibited statistically significant reductions in concentrations in laser-irradiated cultures versus control cultures. These observations do not support a robust anti-inflammatory effect of Nd:YAG laser irradiation. Further studies should explore the potential impact of Nd:YAG laser irradiation on cytotoxicity and cellular growth kinetics and extend across a range of irradiation parameters and cell types.

The Effects of Intensity, Exposure Time, and Distance of Polymerization Light on Vickers Microhardness and Temperature Rise of Conventional Resin-Based Composite.

(1) Background: This study investigates the effects of curing light intensity, exposure time, and distance on the Vickers microhardness (VMH), hardness bottom-to-top ratio (HR), and temperature rise (TR) of conventional dental resin-based composite (RBC). (2) Materials and Methods: Specimens of one conventional RBC (Tetric EvoCeram, Ivoclar Vivadent) were cured with 12 different curing protocols (CPs), created with three different light intensities (Quartz Tungsten Halogen 300 mW/cm2, LED 650 mW/cm2, LED 1100 mW/cm2), two exposure times (20 and 40 s), and two distances of curing tip (0 and 8 mm). The VMH of top (VMH-T) and bottom (VMH-B) surfaces was measured. The hardness bottom-to-top ratio (HR) was calculated from VMH-B and VMH-T. The HR below 80% was rated as inadequate polymerization. The TR at the depth of 2 mm within the RBC was measured using a K-type thermocouple. Data were analyzed using Levene's test and the multivariate analysis of variance (MANOVA). The level of significance was set at p < 0.05. (3) Results: Exposure time and distance significantly influenced VMH-B and HR. Increased distance significantly reduced VMH-B, HR, and TR. CPs 300 mW/cm2/8 mm/20 s and 650 mW/cm2/8 mm/20 s produced inadequate polymerization (HR < 80%). Prolonged exposure time produced higher values of VMH-B and HR. The TR was significantly influenced by light intensity and distance. (4) Conclusions: Suboptimal light intensity (<800 mW/cm2) can produce inadequate polymerization at the lower side of the composite layer when used from a distance. Prolonged irradiation can improve the polymerization to a certain extent. Clinicians are advised to monitor the intensity of the LCUs in order to optimize the photopolymerization process. Caution is required when polymerizing with high-intensity curing light in direct contact with the RBC with longer exposure times than recommended.

In vitro Antileishmanial Effect of Scrophulariabavanatia Extract on Leishmania (L) tropica [MHOM/NADIM3

Background: Cutaneous Leishmaniasis (CL) is a widespread parasitic disease that causes skin lesions and ulcers. Although the World Health Organization recommends Glucantime as a treatment for CL, this remedy presents unexpected side effects and high costs. This study investigates the in vitro antileishmanial effect of Scrophulariabavanatia hydroalcoholic extract on Leishmaniatropica promastigotes. Objectives: This study aims to evaluate the in vitro antileishmanial effects of a local Scrophulariabavanatia hydroalcoholic extract on Leishmania (L.) tropica [MHOM/NADIM3] promastigotes. Methods: Various concentrations (0.2, 1, 5, 25, and 125 mg/mL) of Scrophulariabavanatia methanol extract were prepared and added to cultures containing the parasite. The amastigote form of the L. tropica strain [MHOM/IR/NADIM3] was isolated from mouse spleens and transformed into promastigotes in Novy-Nicolle-Mac Neal medium. The antileishmanial activity of Scrophulariabavanatia extract was then compared to Glucantime using cell proliferation ELISA. Results: The LC50 values in the stationary stage for both Scrophulariabavanatia extract and Glucantime (mg/mL) were greater than in the dynamic stage. The extract at concentrations of 0.2, 1, 5, 25, and 125 mg/mL did not show significant differences after 24 and 48 hours (P &gt; 0.05) compared to negative controls but did show a significant effect after 72 hours (P = 0.000). The extract demonstrated increased effectiveness with higher concentrations and longer exposure times. Conclusions: Scrophulariabavanatia extract inhibits the survival and growth of Leishmania promastigotes. Future studies should further explore its effects on in vivo survival of the parasite.

Mechanical Properties and Microstructural Characteristics of Steel Pipes after Long-Time Hydrogen Exposure

There are three possibilities to transport hydrogen by high pressure pipeline (i) blending hydrogen into the existing natural gas pipeline system, (ii) after checking the integrity, using the natural gas transporting pipeline system to transport hydrogen, (iii) building a new pipeline system to transport pure hydrogen. In all three cases should be known the behaviour of the pipe material and its welded joints influenced under high pressure hydrogen. For this aim pipeline sections made of P355NH base material were investigated without and with hydrogen exposure, where the exposure time was 41 days. Gas metal arc welding and hybrid tungsten arc welding / gas metal arc welding were applied for preparation of the girth weld joints. Tensile, three point bending and hardness tests, furthermore microstructural investigations were performed both on base materials and girth welds of the pipeline sections. The testing results were analysed and compared with each other (base material vs. welded joints, without exposure vs. with exposure) and with limit values can be found in the literature. Conclusions were drawn on the behaviour of the investigated pipe material and its welded joints.

Quantifying motion blur by imaging shock front propagation with broadband and narrowband X-ray sources

Time-integrated radiography using MeV Bremsstrahlung X-ray sources is the norm for imaging during system-level testing of components and structures under dynamic condition. One source of error in the analysis of the time-integrated radiography data sets stems from motion blur which smears out sharp interfaces to a greater degree with longer exposure times, which become necessary to provide sufficient signal-to-noise with low X-ray penetration of objects of interest. To quantify motion blur, a 1D shock wave through PMMA was investigated experimentally at The Dynamic Compression Sector at The Advanced Photon Source (DCS@APS) with tapered broadband and 25.46 ± 1.06 keV narrowband X-rays. Four cameras with different exposure times were used for each experiment to compare the effect that exposure time has on motion blur. In addition, our methodology to accurately simulate motion blur in terms of transmission and shape is presented and compared to our experimental results and quantified. There is a high level of agreement between the experimental and simulation results across the range of data sets investigated in this study with a percent difference range of 0.29–1.31% for the four shots. The methodology of this work serves as a steppingstone towards a physically validated model that could be used in conjunction with experimental results to deconvolve physical parameters, densities, and interfaces of interest in a way that would not be possible with experimental results alone.

The Harmful Effects of Welding Fumes on Human Dental Enamel-A Microhardness Analysis.

Introduction: Over the years, welding fumes' harmful effects have been demonstrated countless times in the scientific literature. Recently, studies in the field have shown an increasing interest in the negative consequences that these fumes may have on the tissues of the oral cavity. Materials & method: The current study aimed to investigate the impact that welding fumes have on the structure of human dental enamel by analyzing the microhardness of the dental enamel in 15 extracted human teeth, after various exposure times, using the Vickers method. Results: The results obtained after 48, 96, 168, and 336 h of direct exposure of the extracted specimens to the welding fumes show a statistically significant increase in the depreciation of the dental enamel's microhardness, related to the duration of exposure (p < 0.05). An average of 305 Vickers units was observed at the longest exposure time, 336 h, in the present study, whereas in the control group, the microhardness analysis showed an average of 327 Vickers units.